Save engineers and judge (6)
I believe the answer is:
redeem
'save' is the definition.
(synonyms)
'engineers and judge' is the wordplay.
'engineers' becomes 're' (Royal Engineers).
'and' is a charade indicator (letters next to each other).
'judge' becomes 'deem' (I've seen this before).
're'+'deem'='REDEEM'
(Other definitions for redeem that I've seen before include "Save from hell or recover from pawn" , "Save, from hell or pawnbroker" , "Free - retrieve" , "Retrieve from hell or pawn" , "take back pawn move" .)